Automatic film processing device



June 1970 c. c. ATTRIDGE ETAL 3,515,050

AUTOMATIC FILM PROCESSING DEVICE Filed Aug. 1, 1967 PRE-DEVELOPMENT 0' LREVIEW OF f FREE-DEVELOPMENT FILM v l8 CONTROL MEANS f FINAL M16DEVELOPMENT 58 DELAY CONTROL MA Z 0/? WR/GH 7' INVENTORS.

United States Patent 01 fice 3,515,050 Patented June 2, 1970 AUTOMATICFILM PROCESSING DEVICE Curtis C. Attridge, 12 Devon Drive, Endicott,N.Y. 13670, and Malor Wright, Bedford Road, Lincoln, Mass. 01773Continuation-impart of application Ser. No. 285,290, June 4, 1963. Thisapplication Aug. 1, 1967, Ser. No. 657,558

Int. Cl. G03d 13/ US. Cl. 95-89 6 Claims ABSTRACT OF THE DISCLOSUREApparatus for accurately controlling the development of a film strip.The film strip is partially developed in a developing bath and thenpasses into a density measuring station having a light source on oneside of the film strip and a photodetector on the other side of the filmstrip. When the film passes out of the first developing bath, it carrieswith it a certain amount of developing solution. The measured density isused to control the output of a cathode ray tube. Electron bombardmentof the faceplate of the cathode ray tube causes emission of heat whichin turn acts on the developing solution which is carried by the filmstrip to accurately control the development of the film. After passingby the cathode ray tube, the film proceeds to a final developing bathwhere developing is completed. In a second embodiment, the densitymeasurement is made at the cathode ray tube.

CROSS-REFERENCE This application is a continuation-in-part ofapplication Ser. No. 285,290, now abandoned, filed June 4, 1963, forAutomatic Film Processing Device and Method, and is related toapplication Ser. No. 638,163, filed Mar. 10, 19,67, for Automatic FilmProcessing Device and Method which is a continuing application of Ser.No. 285,421, now abandoned, filed June 4, 1963.

SUMMARY OF THE INVENTION This invention relates to film processingdevices and more particularly to an automatic and accurately controlleddeveloping device.

While the following description will be directed to the processing ofaerial reconnaissance film, it is not intended that the broad concept beso limited since it will become obvious to those skilled in the art thatwhat is herein disclosed is applicable to processing of any type offilm.

Resolution of fine detail, a factor of paramount importance inphotographic reconnaissance, severely restricts the choice of exposurelatitude of reconnaissance film principally because the degree ofdetailrecorded (resolution) is at least partially dependent uponobtaining an optimum negative density for the scene recorded on thefilm. Controlled processing, which in effect has the capability ofextending the range of exposure for a given level of resolution, istherefore an extremely important and critical means of increasing theamount of information that can be extracted from a given photographicexposure.

The prior art discloses many techniques to vary the contrast and/ordensity of the image, during the course of processing and retrieving thelatent image placed on the film. One of these techniques is to vary thetemperature of the developing solution. This has rather obvious defectsin that, when one portion of a negative is being developed at a givensolution temperature and a given time, these parameters may not beapplicable to the next succeeding portion of the film. As a result, acompromise had to be achieved and it became possible for the parametersso compfiomised to be unsatisfactory for major portions of the Stillanother method available to the prior art was one which involvedincreasing the agitation or activity of the solution over various partsof the film. This, too, had obvious disadvantages in that the increasedactivity could only be viewed at a considerably later period of time andit was possible to increase the activity at an area where, for example,decreased activity was desirable.

Our invention overcomes the difficulties of the prior art by providingincreased solution activity at selectable portions on a film stripautomatically where the amount and the duration of activity can beaccurately controlled over smaller portions of the film than haspreviously been possible or practical.

DESCRIPTION OF THE DRAWING The features of" our invention which webelieve to be novel are set forth with particularity in the appendedclaims. Our invention itself, however, both as to its organization andmethod of operation together with further objects and advantagesthereof, may best be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a block diagram in flow chart form of our processing device;

FIG. 2 is one embodiment of our invention utilizing an electron beamtube as a source of energy to control the temperature of development atdiscrete areas of the film;

and

FIG. 3 is another embodiment of the invention utilizing an electron beamtube as a source of energy for both controlling the temperature of thedevelopment process and for making density measurements.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS Although the particularembodiments of the invention discussed hereinafter disclose the use ofconventional developing fluids for use with particular silver halidefilms, it is to be fully understood that the invention is not solimited. Such embodiments merely are illustrative of par ticular mannersof practicing the invention and as such should in no way be read aslimiting the inventive concept beyond the limitations expressly setforth in the appended claims. For example, infrared radiation isdisclosed as the source of scanning the film for density measurements.If other forms of radiation are developed which will not expose areas ofthe film, such radiation may be used to measure the sensitivity of thesilver halide film. The invention is in no way limited to the use ofsilver halide film but is broad enough to encompass any chemicallyprocessed photosensitive material that may be scanned for densitymeasurement without further exposing the material.

Referring now to FIG. 1 there is depicted the basic concept of ourinvention in flow chart form, showing a film predevelopment stage 10,stage 14 previewing the predevelopment film and a final developmentstage 16. At the previewing stage 14 signals are developed which aretransmitted to a control means 18. These signals are developed byscanning incremental portions of the film to determine the density ofthese incremental portions. Control signals from control means 18 aretransmitted to the final development stage 16 to produce the desireddevelopment activity which in turn produces a film with an image ofuniform developed density regardless of inconsistencies in the image asit is placed on the film and an inconsistency in the predevelopment andin the development chemistry and transport means. In addition, there isshown a stop bath 12 between the predevelopment stage 10 and the reviewof predeveloped film or preview stage 14. The stop stage 12 may benecessary in some instances and has been shown to include a dotted lineextending between predevelopment stage and preview stage 14. Theoptional stop stage 12 is necessary in those instances where sufficienttime elapses between predevelopment stage 10 and preview stage 14 tocause excessive development and merely serves to inhibit suchdevelopment. However, when very little, if any, time elapses betweenstages 10 and 14, stop stage 12 may be unnecessary.

Application Ser. No. 638,163 discloses and claims a number of methodsand apparatus for practicing the inventive concept described above byutilizing various sources of heat energy to control the rate ofdevelopment of the film. Exemplary of the energy sources disclosed areR.F. coils and dielectric heating means. The embodiments illustrative ofthe inventive concepts disclosed and claimed as part of this inventionare shown in FIGS. 2 and 3 herein.

Referring now to FIG. 2 there is shown an embodiment of our inventionwherein a raster producing cathode ray tube is utilized to control thedevelopment process. In this embodiment, film is brought into tank 22containing developer solution 24 and drum 26. This is the predevelopmentstage. Film 20 upon leaving tank 22 may, if the path length is great, herequired to have a stop bath 12 interposed between tank 22 and detector50. It is obvious that some developing solution will remain on the film74. As previously stated, this latter mentioned tank may include afurther development process or may be utilized to appropriately stop anyfurther action on the development of the film.

In another embodiment of the invention the infrared generator 48 is notutilized. In this embodiment, shown in FIG. 3, the beam of cathode raytube 68 may either be deflected in the same manner as a flying spotscanner or, may be made to scan along a single line. Detector 50 isplaced on the under side of film 20 to detect the energy emanating fromfaceplate 69 that passes through film 20. This also obviates the needfor scan synchronization stage 60 since the detector will always knowthe instantaneous of this film appears on pages 50 and 51 of the Seventhwhile traveling from tank 22 to detector 50 and development will occurover this path length.

As film 20 progresses to detector 50, the level of predevelopment isdetected by means of infrared generator 48 and photoelectric cell 50.Infrared generator 48 emits 'rays of infrared energy which are collectedand detected 'by infrared sensitive photoelectric cell 50. At thispoint,

there will be an appreciable amount of metallic silver due to thepredevelopment. Silver halide, the material in the undeveloped emulsion,is a whitish-looking material having a degree of transparency of about40 to 60 percent and a reflectance of about 60 to 40 percent dependingupon the condition and type of film. Such factors as the degree ofwetness, amount of predevelopment and the like, govern the relativereflectance and transmissiveness of the film to infrared radiation.Metallic silver is a blackish material and hence substantiallynontransmissive; Hence as the density level of the image on the filmincreases with increased development less infrared radiation istransmitted by any discrete area of the film and less radiation isreceived by photosensor 50. A decreased current output from thephotoelectn'c cell 50 will be applied to control means 58 to decreasethe output level of energy from the CRT 68.

Immediately after passing detector 50, the film 20 is placed in closeproximity with the faceplate of the cathode ray tube 68. In thisembodiment, a thin film of metal, such as columbium, is deposited on theinside of the infrared transparent cathode ray tube faceplate 69 ofcathode ray tube 68 and the metal film is bombarded with electrons.Bombarding the metal film with electrons produces a moving spot ofinfrared energy which is radiated onto the film. The water embedded withthe emulsion will absorb the energy thereby increasing developmentactivity. This heated emulsion will now produce increased activity inthe developer solution embedded in the emulsion. The amount of heatnecessary is determined by the development detector 50, the output ofwhich is applied to delay/ control means 58 and to a scanningsynchronizer 60. Here, too, it is necessary for the infrared anddetecting radiating device 50 and 48 respectively to scan across thefilm and the appropriate scan information is applied to deflectingplates 66. Simultaneously the detector output information is applied tothe delay/ control means 58 the output of which is applied to grid 64 ofthe cathode ray tube to appropriately modulate the electrode beamemanating from cathode 62. Thereafter the film proceeds to tank 72 inwhich is contained an appropriate developer Edition, first 1956 printingof Kodak Films available from Eastman-Kodak Company, Rochester, NY. Ade' veloping bath that may be used is Kodak Developer D-76, the chemicalconstituents of which are set forth on page 42 of the Fifth Edition(1954) first 1959 printing of Processing Chemicals and Formulasavailable from Eastman-Kodak Company, Rochester, NY. Typical treatmentof the film may be a predeveloped time period of three minutes, that is,any one point on the film would travel from entry into bath 24 to apoint the CRT 68 in a period of three minutes. Radiation treatment ofthe film is instantaneous. The final development time, for example, maybe five minutes, that is, the period it takes for any one point on thefilm to travel from roller 38 to stop bath solution not shown. A typicalstop is Kodak SB-la, the formulation of which is found on pages 44 and45 of the Fifth Edition of Processing Chemicals and Formulas. The CRTmay be activated by a current suitable to raise the temperature of thedeveloping solution D-76, from 68 F. to F., increasing the density ofthe discrete area of the film so treated from 1.2 to 1.5 and increasinggamma from 0.85 to 1.00.

. It is to be fully appreciated that the times quoted hereinabove fordevelopment are limited only to the use of the particular developingsolution D-76 and that high speed developers would work as well as theD-76 developer with the added feature of more rapid total time ofdevelopment. For example, rather than the 12 minutes disclosed withrespect to D-76 developers are marketed with developing times of amagnitude of the order of 10 seconds. It is fully understood that the invention is in no way limited by the use of D-76 developing solution butit is within the concept of the invention to use available developingsolutions and solutions which may become part of the art as advances aremade.

Final development time may be approximately seven minutes. That is atotal time of 8 minutes for a point on the film to run through bath 74which may also be D-76 solution. It is obvious that a more concentratedsolution might be used in bath 74 to decrease the time that any point onthe film takes in the final development bath or a solution with morerapid'development properties might be used.

Thus, an automatic film processing device and method which overcomes thedifficulties of the prior art by providing increased solution activityat selectable incremental portions of the film step automatically hasbeen fully and completely disclosed. While we have described what ispresently considered a preferred embodiment of our invention, it will beobvious to those skilled in the art that various changes andmodifications may be made therein without departing from the inventiveconcept,

and it is aimed in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of our invention.

What is claimed is:

1. Chemical processing apparatus for developing a photographic materialcomprising:

(a) means to partially develop said photographic material;

(b) means to measure the density of the partially developed material;and

(e) means to control further development of said photographic materialin response to said density measurement said means including a cathoderay tube means to control the further development by the application ofheat to the photographic material, said cathode ray tube means having afaceplate which generates heat upon electron bombardment.

2. Apparatus as. set forth in claim 1 wherein said density measuringmeans includes a separate density measuring station which is distinctfrom said controlling means.

3. Apparatus as set forth in claim 1 wherein said density measuringmeans directs infrared radiation at the photographic material to measureits density.

4. Apparatus as set forth in claim 2 including a synchronizing means tosynchronize operations of said density measuring means and saidcontrolling means.

5. Apparatus as set forth in claim 1 wherein said density measuringmeans utilizes the output of said cathode ray tube.

6. Apparatus as set forth in claim 1 wherein the chemical processingapparatus includes a final developing bath for the photographic materialafter it is treated by said controlling means.

References Cited UNITED STATES PATENTS 1,762,936 6/1930 Seymour 95--94XR 1,895,760 1/1933 Hunt 95-89 2,989,909 6/ 1961 Reed 355---20 XR NORTONANSH-ER, Primary Examiner F. L. BRAUN, Assistant Examiner

